When use cv::VideoCapture I get green and purple image #81

fukamike · 2019-12-04T06:22:26Z

When I use cv::VideoCapture I get green and purple image.
I want to get right image and left image using cv::VideoCapture.

fukamike · 2019-12-04T06:24:04Z

fukamike · 2019-12-04T06:26:17Z

I'm using this code and compile.
`#include
#include "opencv2/opencv.hpp"

int main(int argh, char* argv[])
{
const std::string WIN_NAME = "Capture";
const int CAP_WIDTH = 752;
const int CAP_HEIGHT = 480;
// const std::string SAVE_FILE = "Img.jpg";

//デバイスのオープン
cv::VideoCapture cap(0);
//cap.open(0);

//オープン失敗？
if(!cap.isOpened())
{
    std::cout << "ERROR: cannot open cam device." << std::endl;
    return -1;
}

//キャプチャサイズの設定
cap.set(CV_CAP_PROP_FRAME_WIDTH, CAP_WIDTH);
cap.set(CV_CAP_PROP_FRAME_HEIGHT, CAP_HEIGHT);

//ループ
while(1)
{
    cv::Mat frame;
    // 1フレームキャプチャ
    //cap >> frame;
    if (!cap.read(frame))
    {
        std::cout << "ERROR: cannot capture." << std::endl;
        break;
    }

    //表示
    cv::imshow(WIN_NAME, frame);

    //キー待ち
    int inp_key = cv::waitKey(1);

    //入力あり？
    if (inp_key >= 0) {
        // [ESC] or 'Q' or 'q'
        if (inp_key == 27 || inp_key == 81 || inp_key == 113) break;

        // 'S' or 's'
        //else if(inp_key == 83 || inp_key == 115)
        //{
        //  //フレーム画像を保存する
        //  cv::imwrite(SAVE_FILE, frame);
        //}
    }
} //end of while

//ウィンドウ破棄
cv::destroyAllWindows();

return 0;

}`

g++ camera.cpp -I/usr/local/include/opencv2 -I/usr/local/include/opencv -L/usr/local/lib -lopencv_core -lopencv_imgcodecs -lopencv_highgui -lopencv_video -lopencv_videoio

harjeb · 2019-12-04T06:37:12Z

You need spilt raw data like:

    // Split raw data to two images
    const int &w = raw.cols, &h = raw.rows;
    const int size = w * h;
    if (left.cols != w || left.rows != h || left.type() != CV_8UC1)
        left = cv::Mat(h, w, CV_8UC1);
    if (right.cols != w || right.rows != h || right.type() != CV_8UC1)
        right = cv::Mat(h, w, CV_8UC1);
    unsigned char *data = raw.data;
    for (int i = 0; i < size; ++i) {
        left.data[i] = data[i*2];       // Y1   Y2
        right.data[i] = data[i*2 + 1];  //    U    V
    }
    cv::imshow("left", left);
    cv::imshow("right", right);

fukamike · 2019-12-04T07:46:37Z

I succeed compile and run program.
I indicate the result.

`#include
#include "opencv2/opencv.hpp"

int main(int argh, char* argv[])
{
const std::string WIN_NAME = "Capture";
const int CAP_WIDTH = 752;
const int CAP_HEIGHT = 480;
// const std::string SAVE_FILE = "Img.jpg";

//デバイスのオープン
cv::VideoCapture cap(0);
//cap.open(0);

//オープン失敗？
if(!cap.isOpened())
{
    std::cout << "ERROR: cannot open cam device." << std::endl;
    return -1;
}

//キャプチャサイズの設定
cap.set(CV_CAP_PROP_FRAME_WIDTH, CAP_WIDTH);
cap.set(CV_CAP_PROP_FRAME_HEIGHT, CAP_HEIGHT);

//ループ
while(1)
{
    
    cv::Mat frame;
cap >> frame;
cv::Mat left;
cv::Mat right;
const int &w = frame.cols, &h = frame.rows;
	const int size = w * h;
	if (left.cols != w || left.rows != h || left.type() != CV_8UC1)
   		 left = cv::Mat(h, w, CV_8UC1);
if (right.cols != w || right.rows != h || right.type() != CV_8UC1)
   		 right = cv::Mat(h, w, CV_8UC1);
	unsigned char *data = frame.data;
	for (int i = 0; i < size; ++i) {
    	left.data[i] = data[i*2];       // Y1   Y2
    	right.data[i] = data[i*2 + 1];  //    U    V
	}
	cv::imshow("left", left);
	cv::imshow("right", right);
    // 1フレームキャプチャ
    //cap >> frame;
    //if (!cap.read(frame))
    //{
    //    std::cout << "ERROR: cannot capture." << std::endl;
    //    break;
    //}

    
    //キー待ち
    int inp_key = cv::waitKey(1);

    //入力あり？
    if (inp_key >= 0) {
        // [ESC] or 'Q' or 'q'
        if (inp_key == 27 || inp_key == 81 || inp_key == 113) break;

        // 'S' or 's'
        //else if(inp_key == 83 || inp_key == 115)
        //{
        //  //フレーム画像を保存する
        //  cv::imwrite(SAVE_FILE, frame);
        //}
    }
} //end of while

//ウィンドウ破棄
cv::destroyAllWindows();

return 0;

}`

fukamike · 2019-12-04T07:52:07Z

I want to get left image and right image from mynt-eye s1030 using cv::VideoCapture.
Like this image.

flinnna · 2019-12-04T08:09:38Z

you can refer to code below.

#include "camera.hpp"

// https://stackoverflow.com/questions/10167534/
// how-to-find-out-what-type-of-a-mat-object-is-with-mattype-in-opencv
/*
std::string type2str(int type) {
    std::string r;

    uchar depth = type & CV_MAT_DEPTH_MASK;
    uchar chans = 1 + (type >> CV_CN_SHIFT);

    switch ( depth ) {
        case CV_8U:  r = "8U"; break;
        case CV_8S:  r = "8S"; break;
        case CV_16U: r = "16U"; break;
        case CV_16S: r = "16S"; break;
        case CV_32S: r = "32S"; break;
        case CV_32F: r = "32F"; break;
        case CV_64F: r = "64F"; break;
        default:     r = "User"; break;
    }

    r += "C";
    r += (chans+'0');

    return r;
}
*/

int main(int argc, char const *argv[]) {
    int index = 0;
    if (argc >= 2) {
        try {
            index = std::stoi(argv[1]);
        } catch (...) {
            std::cout << "Warning: Can't set index: " << argv[1] << std::endl;
        }
    }
    Camera cam(index);
    if (!cam.IsOpened()) {
        std::cerr << "Error: Open camera failed" << std::endl;
        return 1;
    }
    std::cout << "\033[1;32mPress ESC/Q to terminate\033[0m\n";

    //std::cout << cv::getBuildInformation();

    // cv::VideoCaptureProperties:
    // http://docs.opencv.org/master/d4/d15/group__videoio__flags__base.html#gaeb8dd9c89c10a5c63c139bf7c4f5704d

    // For get raw camera data with v4l2
    std::cout << "CAP_PROP_CONVERT_RGB disabled: "
        << cam.Set(cv::CAP_PROP_CONVERT_RGB, 0)
        << std::endl;
    std::cout << "CAP_PROP_FORMAT: " <<
        cam.Get(cv::CAP_PROP_FORMAT) << std::endl;

    std::cout << std::flush;

    //cv::Mat frame;
    cv::Mat left, right;
    cam.Capture([&cam/*, &frame*/, &left, &right](
            const cv::Mat& raw, const cv::Mat& depthmap) {
        //std::cout << "type: " << type2str(raw.type()) << std::endl;
        /*
        cv::cvtColor(raw, frame, cv::COLOR_YUV2BGR_YUY2);
        cam.DrawInfo(frame);
        cv::imshow("camera", frame);
        */

        // Split raw data to two images
        const int &w = raw.cols, &h = raw.rows;
        const int size = w * h;

        if (left.cols != w || left.rows != h || left.type() != CV_8UC1)
            left = cv::Mat(h, w, CV_8UC1);
        if (right.cols != w || right.rows != h || right.type() != CV_8UC1)
            right = cv::Mat(h, w, CV_8UC1);

        unsigned char *data = raw.data;
        std::cout << "type: " << raw.data[0] << std::endl;
        for (int i = 0; i < size; ++i) {
            left.data[i] = data[i*2];       // Y1   Y2
            right.data[i] = data[i*2 + 1];  //    U    V
        }
        cv::imshow("left", left);
        cv::imshow("right", right);

        char key = (char) cv::waitKey(10);
        return !(key == 27 || key == 'q' || key == 'Q'); // ESC/Q
    });

    return 0;
}

fukamike · 2019-12-04T09:37:09Z

what is camera.hpp?

flinnna · 2019-12-04T09:38:58Z

camera.hpp

#ifndef CAMERA_HPP_
#define CAMERA_HPP_
#pragma once

#include <functional>
#include <iostream>
#include <sstream>

#include <opencv2/opencv.hpp>

class Camera {
public:
    using VideoCapture = cv::VideoCapture;
    using FrameCallback = std::function<bool(const cv::Mat&, const cv::Mat&)>;

    Camera(int index = 0)
            : cap_(new VideoCapture(std::move(index))),
#ifdef USE_OPENNI
              use_openni_(index == cv::CAP_OPENNI || index == cv::CAP_OPENNI2),
#endif
              fps_(-1) {
        int flag = 0;
#ifdef USE_OPENNI
        if (use_openni_) {
            flag = cv::CAP_OPENNI_IMAGE_GENERATOR;
            Set(cv::CAP_OPENNI_IMAGE_GENERATOR_OUTPUT_MODE, cv::CAP_OPENNI_VGA_30HZ);
        }
#endif
        std::cout << "Capture frame width: " << Get(flag + cv::CAP_PROP_FRAME_WIDTH)
            << ", height: " << Get(flag + cv::CAP_PROP_FRAME_HEIGHT)
            << std::endl;
        fps_ = Get(flag + cv::CAP_PROP_FPS);
        std::cout << "Capture fps: " << fps_ << std::endl
#ifdef USE_OPENNI
            << "Use OpenNI: " << use_openni_ << std::endl
#endif
            << std::endl;
    }
    virtual ~Camera() {}

    bool UseOpenNI() {
#ifdef USE_OPENNI
        return use_openni_;
#else
        return false;
#endif
    }

    double Get(int prop_id) const {
        return cap_->get(prop_id);
    }

    bool Set(int prop_id, double value) {
        return cap_->set(prop_id, value);
    }

    bool IsOpened() {
#ifdef USE_OPENNI
        return use_openni_ || cap_->isOpened();
#else
        return cap_->isOpened();
#endif
    }

    void Preview(FrameCallback callback = nullptr) {
        cv::namedWindow("camera", 1);
        Capture([&callback](const cv::Mat& frame, const cv::Mat& depthmap) {
            cv::imshow("camera", frame);
            if (callback && !callback(frame, depthmap)) {
                // return false to break
                return false;
            }
            // return false to break if ESC/Q
            char key = (char) cv::waitKey(30);
            return !(key == 27 || key == 'q' || key == 'Q');
        });
    }

    // callback return true to continue and false to break
    void Capture(FrameCallback callback) {
        if (!callback) {
            std::cerr << "ERROR: Null FrameCallback\n";
            return;
        }

        cv::Mat frame;
        cv::Mat depthmap;
        double t;
        for (;;) {
            t = (double)cv::getTickCount();

#ifdef USE_OPENNI
            if (use_openni_) {
                cap_->grab();

                cap_->retrieve(depthmap, cv::CAP_OPENNI_DEPTH_MAP);
                cap_->retrieve(frame, cv::CAP_OPENNI_BGR_IMAGE);
                //cap_->retrieve(frame, cv::CAP_OPENNI_GRAY_IMAGE);
            } else {
                cap_->read(frame);
            }
#else
            cap_->read(frame);
#endif

            if (frame.empty()) {
                std::cerr << "ERROR: Blank frame grabbed\n";
                break;
            }

            bool ok = callback(frame, depthmap);

            t = (double)cv::getTickCount() - t;
            fps_ = cv::getTickFrequency() / t;
            //std::cout << "fps: " << fps_ << std::endl;

            if (!ok) break;
        }
    }

    double FPS() const {
        return fps_;
    }

    std::string ExtraInfo() const {
        std::ostringstream info;
        info << "FPS: " << fps_;
        return info.str();
    }

    void DrawInfo(const cv::Mat& im) const {
        using namespace std;
        int w = im.cols, h = im.rows;
        // topLeft: width x height
        {
            ostringstream ss;
            ss << w << "x" << h;
            string text = ss.str();

            int baseline = 0;
            cv::Size textSize = cv::getTextSize(text, cv::FONT_HERSHEY_PLAIN,
                1, 1, &baseline);

            cv::putText(im, text, cv::Point(5, 5 + textSize.height),
                cv::FONT_HERSHEY_PLAIN, 1, cv::Scalar(255,0,255));
        }
        // topRight: fps
        {
            ostringstream ss;
            ss << "FPS: " << fps_;
            string text = ss.str();

            int baseline = 0;
            cv::Size textSize = cv::getTextSize(text, cv::FONT_HERSHEY_PLAIN,
                1, 1, &baseline);

            cv::putText(im, text,
                cv::Point(w - 5 - textSize.width, 5 + textSize.height),
                cv::FONT_HERSHEY_PLAIN, 1, cv::Scalar(255,0,255));
        }
    }

private:
    std::unique_ptr<VideoCapture> cap_;
#ifdef USE_OPENNI
    bool use_openni_;
#endif
    double fps_;
};

#endif  // CAMERA_HPP_

fukamike · 2019-12-04T09:53:03Z

Thank you for your adovice.
I was able to get images.

buchi77 · 2020-01-06T06:09:02Z

hi,i copy and paste.
but it doesn't run.

721920 is stored in raw.cols
1 is stored in raw.rows

is this normal?

jyzhong · 2021-03-26T06:49:12Z

Thank you for your adovice.
I was able to get images.

hello, i try what you did. but i failed. The result just like your second picture. can you give me some advice?

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When use cv::VideoCapture I get green and purple image #81

When use cv::VideoCapture I get green and purple image #81

fukamike commented Dec 4, 2019

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harjeb commented Dec 4, 2019

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jyzhong commented Mar 26, 2021

When use cv::VideoCapture I get green and purple image #81

When use cv::VideoCapture I get green and purple image #81

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fukamike commented Dec 4, 2019

fukamike commented Dec 4, 2019

fukamike commented Dec 4, 2019

harjeb commented Dec 4, 2019

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flinnna commented Dec 4, 2019

fukamike commented Dec 4, 2019

flinnna commented Dec 4, 2019

fukamike commented Dec 4, 2019

buchi77 commented Jan 6, 2020

jyzhong commented Mar 26, 2021